The present invention relates generally to a cushioning assembly comprised of a foam body with individual spring units imbedded within it.
Conventional cushions made from a combination of wire springs and resilient foam, such as are commonly utilized in seat cushions and the like, are typically fabricated by encasing an assembly of individually pocketed and interconnected coil springs in resilient polyurethane foam and then wrapping the foam in either polyester fiber batting or in a plush down wrapping. In particular, the coil springs are normally cylindrical in shape and connected together, either by a system of connecting clips or continuous wire, and foam pieces are glued together to form an outer envelope around the springs. In some spring/foam cushioning assemblies, each spring may be enclosed within an individual nonwoven sock for additional sound dampening of contact between the springs.
Spring/foam cushioning assemblies are desirable because of their ability to integrate the soft cushioning of foam with the resilient support of springs. Use of foam with sufficient compressibility to provide comfortable cushioning, alone, would not provide sufficient support to maintain the foam's integrity against the cushioned body. Hence, spring units are employed to generate a restoring force against the cushioned body once the foam has been compressed a certain amount, thereby supplying support of the cushioned body. Use of springs units alone, on the other hand, is not desirable because of the inability of springs to absorb and retain an impacting force, i.e., foam provides a dampening effect because of its ability to compress and remain compressed. Alternatively, while not exhibiting undue oscillation, use of springs with high spring constants would feel hard and firm, and generally would not be thought of as comfortable.
Spring/foam cushioning assemblies are also desirable because of their ability to maintain their shape after many years of use.